Many residential garages are equipped with an operator for providing electromechanical movement of the garage door between an open position and a closed position. Various systems have been devised for attaching the operator to the garage door to effect such movement. These systems may include a cable, a belt, or a threaded shaft commonly referred to as a worm shaft.
For many residential owners, the installation of a garage door seems a relatively easy, do-it-yourself task. Instruction manuals are presented with detailed pictures and precautions to guide people through the steps, necessitating equipment as common as a screwdriver and a power drill. Before beginning installation, however, the would-be installer must first acquire or purchase the system and transport it to the installation site.
One of the issues presented with transporting the operator system to the installation site is the size of the system. When the movable barrier or door is in an open position, most garages provide an opening roughly equivalent to what one would expect from a standard door frame, approximately eighty inches. A typical garage door will, in the closed position, rest on a ground surface such as a garage floor and generally span the garage door opening. To open the garage by moving the door to the open position, requires the door to shift from contact with the ground surface to a position sufficient to allow passage for cars or people or other items through the garage opening. That is, the door will travel approximately eighty inches between the open and closed position. For taller garage openings equipped with larger doors, it may be desired for the door to travel a distance greater than eighty inches.
For operator systems utilizing a worm shaft, the distance the door must travel determines, to some extent, the length of the worm shaft that must be transported to an installation site. That is, the shaft must be of sufficient length to provide for the described amount of travel. Though some people have uncommonly large automobiles or other vehicles that may provide for a shaft having an eight-foot length, many people find it cumbersome and difficult to load such an item into their car. Additionally, the operator system is desirably packaged and sold in a single carton, inside of which includes a generally rectangular operator box including a motor and a connection for the worm shaft, the worm shaft itself along with a supporting rail, and hardware components for coupling the rail and shaft with the garage door and for mounting the operator box in the garage, such as to a ceiling or rafter support. Were the rail and shaft a single component of eighty or more inches, and this were packaged in a single carton with a relatively heavy operator box, the entire carton can prove unwieldy for many people.
In order to address this problem, there are a number of currently known approaches for providing a worm shaft having a plurality of shorter segments which are coupled together. In this manner, the operator system may be packaged in a smaller and easier-handled carton. A user or installer may then assemble the segments into the full-length worm shaft prior to installation.
One example of an segmented shaft is described in U.S. Pat. Nos. 4,352,585, and 5,085,094. To form a connection or joint between first and second shaft segments, cooperating structure is provided on the ends of the shafts. More particularly, each joint end is generally cylindrical and includes a first cut section at a first depth to form a surface parallel to the longitudinal axis of the shaft, and a second cut section at a second depth greater than and parallel to the first depth. The second cut section is made further away from a shaft terminus so that it forms a notch in the cylindrical end. Respective notches in the first and second shaft segments are joined so that the first cut section of the first segment is mated with the second cut section of the second segment, and the second cut section of the first segment is mated with the first cut section of the second segment. In this manner, the mated end portions including the cut sections together form a cylindrical outer surface.
The end portions must be maintained in the mated relationship. To accomplish this, a full ring piece is positioned around the cylindrical portion of one of the segments so that it is clear of that segment's notch prior to mating with the other segment. Once mated, the ring is slid over the notches to hold the segments together. Lastly, a partial ring is snapped onto the portion from where the ring is slid to prevent the full ring from backing away from the joint.
With the described notched-connection utilizing the rings, a number of components and steps are required for assembly. Users or installers are required to first slide on the full ring as a separate component, then couple the notches, slide the ring over the joint, then snap on the separate component of the partial ring. This requires a user to keep track of small components and to manipulate the small components in conjunction with the large shaft segments.
Accordingly, there has been a need for a simpler and more user-friendly assembly and joint for a shaft for a movable barrier operator system.